object ScalaVarDemo022 {
  def main(args: Array[String]): Unit = {

    var num1 = 1.2
    var num2 = 1.7f

    num2 = num2.toFloat
    println(num2)

    println(num2.isInstanceOf[Double])
    println(num2.isInstanceOf[Float])
    println(sayHello)
  }

  def sayHello(): Nothing = {
    throw new Exception("抛出异常")
  }
}
